I recently got a Matrox Impression Lite with 2 MB as PCI card using a IS-ATHENA R2 chip from 1995 and a seperated CL-PX2085 DAC. The card has a EEPROM BIOS.

I first tried with Win98SE which brings already a driver for it. There was nothing really special about it.
Then I tried the Win95 driver which brings Powerdesk and some tools, but also nothing real special. 2D-Performance was in both cases good.

I noticed that in DOS there is no VESA support from BIOS at all.
320x200 at 256 colors is utterly slow, with about 12 fps in Duke3D and vidspeed reported a performance of an old 8 bit ISA VGA card. (about 8 times slower than a ISA TSENG ET4000).
I looked for a VESA driver and found one in the Windows 3.x software.
It supports VESA 1.2 and enables up to 1024x768 at 256 colors interlaced.
So I tried Duke3D again at 640x480 and 800x600 which gives 1-2 fps, you can watch the screen repainting. Same applies for Descent2...
Then there is some ominous setvga tool which has a -m1 and -m2 parameter and is no TSR, just changes some hardware setting.
So -m2 increased the 320x200 mode performance to 22 fps in Duke3D which is ok. VESA mode performance did not increase.
The speed difference between Windows and DOS is astonishing.
(kind of DOS gaming protection for CAD engineers 😉 ).

I also found a board information tool for Win 3.x and it works also in Win 9x:

So what about this 3D Wireframe Acceleration?

I looked into some readmes and there is a 3D Screensaver mentioned on the Supplemental Disk. After further search I found it there
ftp://ftp.matrox.com/pub/mga/othermga/previous/15512220.zip

The disk also includes a VfW 1.1d DCI driver and a Dynaview3D Application for AutoCAD12 and 13 models. The Screensaver needs a AutoCAD model to show. Now it looks that this API is only available from Windows 3.x since Dynaview3D can not load a required sxci library.
Also the Screensaver just shows a 2D Matrox logo and it does not matter which 3D model I choose.

So next time I try with this card I should go for a Win 3.x setup.